Vibratory bin agitator



Jan. 19, 1965 P. H. SCHRADER 3,166,222

VIBRATORY BIN AGITATOR Filed Aug. 11, 1961 '"III. ,23

3 Sheets-Sheet l Jill Fig. 3

INVENTOR. PRESTON H. SCHRADER ATTORNEYS Jan. 19, 1965 P. H.'SCHR'ADER3,166,222

VIBRATORY BIN AGITATOR Filed Aug. 11, 1961 5 Sheets-Sheet 2 INVENTOR. l4PRESTON H. SCHRADER M iM -CM ATTORNEYS Jan. 19, 1965 P. H- SCHRADER3,166,222

VIBRATORY BIN AGITATOR Filed Aug. 11 1961 3 Sheets-Sheet I5 "("I'I'I'lwiliiiappa...

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ATTORNEYS IN PRESTON H. SCHRADER United States Patent 3,166,222VIBRATORY BIN AGITATOR Preston H. Schrader, Louisville, Ky., assignor toRex Chainhelt Inc, a corporation of Wisconsin Filed Aug. 11, 1961, Ser.No. 130,892 9 Claims. (Cl. 222-155) This invention relates to vibratorybin agitators and in particular to be an improved agitator that can beeasily adapted for use in various types of storage bins to promote thefree uniform flowing of powdery material from such bins.

Many powdery materials when stored in funnel shaped hoppers tend to archor bridge and thus refuse to flow evenly when the bottom of the hopperis opened. It is also characteristic of these materials that when thearch is broken the material tends to fall so freely that it flushes outand thus feeds a surge of material into the receiving system.

The principal object of this invention is to provide a simple economicalapparatus for promting the free uniform flow of powdery material fromvarious shaped hoppers or drums.

Another object of the invention is to provide a simple apparatus forevenly distributing an aeriform fluid into the lower portions of ahopper filled with powdery material and mechanically agitating thematerial to promote the free flow of the material as it is drawn fromthe bottom of the hopper.

More specific objects and advantages are apparent from the followingdescription of a preferred form of the invention.

According to the invention a skeleton frame extending across asubstantial portion of a cross section of the hopper is connectedthrough a stem to a vibrating mechanism adapted to produce either avertical or rotary or combined vibration of the frame and thus inhibitthe formation of arches in the powdery material. At the same time anaeriform fluid may be supplied through the stem to the frame fordischarge into the material to further inhibit any tendencies for thematerial to arch.

A preferred embodiment of the invention is illustrated in theaccompanying drawings.

In the drawings:

FIG. 1 is a side elevation of a bin agitator installed in a bin withparts broken away to reveal the structure.

FIG. 2 is an enlarged vertical section of a vibration exciter suitablefor use with the agitator.

FIG. 3 is a vertical section of the lower end of the agitator showingthe air passages therethrough.

FIG. 4 is an enlarged fragmentary vertical section of the agitator.

FIG. 5 is a fragmentary plan view with parts broken away of the agitatorshown in FIG. 4.

FIG. 6 is an enlarged vertical section of one of the arms of theagitator as seen from the line 66 of FIG. 4.

FIG. 7 is a fragmentary side elevation of a modified form of agitatorand diffuser for use in agitating material in bins according to theinvention.

FIG. 8 is a vertical section showing another form of agitator suitablefor use in conditioning powdery material in hoppers or bins.

FIG. 9 is a modified form of the structure shown in FIG. 8.

FIG. 10 is an enlarged figure showing a detail of One of the valves ofthe arrangement shown in FIG. 9.

FIG. 11 is another form of agitator serving also as a valve foradmitting or pumping aeriform fluid into the material being conditioned.

These specific figures and the accompanying descrip- 3,15%,222 PatentedJan. 19, 1965 tion are intended merely to illustrate the invention andnot to impose limitations on its scope.

In the apparatus as shown in FIG. 1 a funnel shaped container 10 isadapted to temporarily store material that is fed in through a chute 11and withdrawn through a restricted bottom portion 12 of the container.Suitable valving mechanism may be included in the lower portion of thecontainer 10 to control the rate of flow of material.

'To prevent arching of the material and to promote uniform flow ofmaterials from the side portions and central portions of the hopper 10,an agitator 13, which preferably comprises a plurality of radiallyextending tubular arms 14, is mounted on the lower end of a stem 15. Theagitator 13 also includes a downwardly directed stem 16 the lower end ofwhich is fitted with a perforated cap 17. The perforations through thecap, as shown in detail in FIG. 3, provide a plurality of air passages18 through which an aeriform fluid may be discharged from the interiorof the agitator 13 into the powdery material at the bottom of the hopper10.

The agitator 13 is preferably carried on the lower end of the tubularstem 15 the upper end of which is rigidly attached to a small platform21 by means of a plurality of gusset plates 22. A vibration generator23, shown in detail in FIG. 2, is suspended by means of a vibrationisolating spring 24 from an overhead structure 25. A safety chain 26 mayalso be employed to catch the vibration generator in the event offailure of the isolating spring 24. The chain 26 may also serve as aguide for electrical power and control leads leading to the vibrationgenerator 23.

As may be seen in FIG. 2 the vibration generator 23 comprises an outerframe 30 which with the stem 15 and agitator 13 forms a work member andan exciter member 31 that is contained within the frame 30 and guided byparallel links 32 arranged to confine the exciter member 31 to asubstantially straight line vertical path. The exciter member 31includes a drive motor 33 that carries eccentric weights 34 on each endof its armature shaft 35. The exciter member 31 is resiliently coupledto the outer frame 30 of the vibration generator 23 by a pair of airsprings 36 and 37 that are connected through restricted air lines to asource of controlled air pressure. Since the spring rate of the airsprings 36 and 37 varies linearly with the inflation pressure it ispossible, by control of such inflation pressure, to vary the couplingbetween the exciter member 31 and the case 30 and thus the vibration ofthe case 30 of the vibration generator 23 in response to the vibratoryforce of the eccentric weights 34.

The agitator 13, as illustrated in detail in FIG. 4, preferablycomprises tubular radially directed arms or spokes 14 that extendlaterally from a central hub 49 which in turn is connected to the lowerend of the stem 15. Braces 41 connected between a collar 42 on the stem15 and the outer ends of the spokes 14 prevent any substantial bendingof the spokes or strain of their threaded connections at the hub 40 inresponse to the vibrational forces.

Each of the spokes 14, as shown, is hollow and is connected to theinterior of the housing 40 so that air or other aeriform fluid suppliedthrough a hose connection 45 and the stem 15 may flow through theinterior of the spokes 14 and out through apertures 46 provided in theirupper surfaces. Each of the spokes is provided with a cap 47 to preventleakage at'its end. Alternatively the apertures 46 may be located in thelower surfaces of the spokes.

The assembly of the spokes 14 to the hub 40 constitutes a skeleton framehaving an outline area substantially coextensive with the tips of thespokes.

To prevent the ingress of powdery material into the spokes 14 throughthe apertures 46 in their upper surfaces semi-cylindrical shells 5d arearranged in overhanging coaxial relation to the spokes 14, thesemi-cylindrical shells being held by bolts 51 and being spaced from thetubular spokes 14 by rubber spacers 52 serving as seals to preventlateral flow of the aeriform fluid along the spokes and forcing thefluid to flow downwardly around the periphery of the spokes 14 and outunder the edges of the coaxial covering shells 5t). Theshells 50 may beomitted when the apertures 46 are located in the lower surfaces of thespokes.

The shells Stl, besides directing the flow of air, also serve toincrease the effective area of the spokes 14 and thus the quantity ofpowdery material in the container it) that is directly influenced by themechanical vibration of the agitator l3. V

Other forms of agitators that may be supported and vibrated by the stem15 are illustrated in FIGS. 7, 8, 9 and 11.

Referring to BIG. 7, a satisfactory agitator may include a flat mixerplate 60 attached to the bottom end of a tubular stem 15d. For diifusingaeriform fluid into the vibrationally agitated material a plurality ofnozzles 61 projecting from the sides of the tubular stem 1511 may beprovided and these may be inclined in various directions to distributethe flow of aeriform fluid. Additionally, radially extending arms orspokes 62 having nozzles or apertures 63 in their lower surfaces may beprovided to still further distribute the fluid and agitate the material.

In this arrangement, as shown in FIG. 7, the vibration of the, flatmixer plate breaks up any tendency for the powdery material to arch orcake in the region above the plate and at the same time by agitating thematerial provides an even distribution of the air or other aeriformfluid distributed through the nozzles 61 or 63. The material is thuskept in a free flowing condition so that all components of the materialmay readily flow down around the edges of the plate 60 and out of thehopper in which the vibratory equipment is used.

In the arrangement as shown in FIG. 8, the agitator comprises an openbottom cone or pyramid 65 connected to the bottom end of a tubular stem15b. In this simple arrangement the vertical vibration of the stern 15bagitates the powdery material over the surface of the cone 1 or pyramidand by keeping (the material, particularly around the outer edges of thecone or pyramid in a state of agitation, allows any air or other fluidsupplied through the tubular stem 15 to escape aroundthe edges of thecone and be evenly distributed throughout the material above the surfaceof the cone. In fact, the vibration of the cone combined with the slopeof its upper surface provides a space into which the air may readilyflow, particularly during the downward portions of the vibratory cycle,to evenly aerate the material and inhibit any tendency of the materialto arch in the hopper and refuse to flow evenly.

If desired, the slant surface of the cone or pyramid 65 may beperforated either in its marginal area or throughout the whole area soas to act as a diffuser admitting the air into the spaces immediatelyabove the conical surface without requiring the air to flow around thelower edge. This latter form is preferable when the projected area ofthe cone or pyramid represents a substantial portion of the area of thehopper in which the equipment is installed.

This particular form is quite eflicient in breaking up any incipientarches of material in the hopper because not only does it'provide avibrational force to mechanically agitate the material but it alsoprovides a pumping action for pumping air through the adjacent materialboth above and below the cone. This pulsating air flow through thepowdery material produces sufficient random motion of the particles ofmaterial to prevent any static settling or steep angles of reposetending to adversely affect the flowability of the material.

FIGS. 9, l0 and 11 illustrate additional modifications to augment thepumping action of the agitator. In the arrangement shown in FIG. 9, aconical or pyramid surface 79 attached to the lower end of a hollowvibratory stern 150 has apertures '71 that are covered by angledeflectors 72 which are illustrated in detail in FIG. 10. Each of thedeflectors 72 may conveniently be formed of a piece of angle iron thatis welded or otherwise attached to the conical surface '70 and which inturn is provided with apertures 73 in its side walls to providefor theescape of air from the space beneath the deflector. The apertures 73 arecovered with resilient fiaps '74 so as to be closed during the upwardmotion of the conical surface 76 in response to the vibration and toopen during downward acceleration to allow air to escape from beneaththe resilient flap and into the material. Since the flap reeloses theaperture 73 at the start of the next upward cycle the net effect is apumping action tending to induce air or other aeriform fluid from thestem lc into the material above the conical surface. In this arrangementthe bottom of the conical agitator may be closed with a bottom plate '75so that all of the air admitted through the stem must flow out throughthe apertures 71' and 73 and under the flap 74 during the vibratorycycle.

The system may also be operated in a manner similar to the operation ofthe agitator shown in FIG. 8 by leaving the bottom of the conicalagitator open, i.e. without the plate '75, in which case some of theair'is exhausted through the open bottom directly into the materialwhile the remainder of the admitted air is pumped out through theapertures 71, 73. This arrangement is particularly elficient when theconical surface is of substantial area, and offers improvedcharacteristics over the perforated cone 65 of FIG. 8 because the flaps74 provide a valving action to prevent the reverse flow of air throughthe apertures. Thus the agitator can act as a pump in promoting aundirectional flow of 'air in addition to the vibratory motion.

The agitator may be modified still further, as shown in FIG. 11, byproviding a hollow vibratory generally flat plate 80 having apertures 81covered by an annular elastorner flap 82 which may be entirely in onepiece or in annular rings as may be desired and which serves as a valveto allow the air to flow during the downward vibratory motion and closethe apertures during the upward motion. The closed bottom of the plate83 of the agitator acts as a ram or piston to provide vibratory forcedriving the material downwardly below the agitator as Well as providingpulsating air motion through the material to break up any tendency toarch in the space directly below the agitator.

While it has been common practice to apply agitators or vibrators to thewalls of funnel shaped bins to. promote the flow of material and whileit has also been known to supply aeriform fluid under pressure throughthe lower portions of such walls to provide fluidization of the materialsuch systems have in general required large amounts of air underpressure or relatively large rnechanic-al elements to provide suflicientvibratory force to break up the arching of materials. 7

These methods are not'entirely satisfactory because some materials Whensubjected to vibration of the container walls tend to pack more solidlythan they otherwise would. In these cases the vibration actuallyaggravates the problem ratherthan curing it. In the improved form asillustrated in the drawings the vibration is applied only to therelatively small members comprising the agitator frame or skeleton frameand, optionally, at the same time a small amount of air may be added topromote the flow of the material. The agitation produced by thevibration of the agitator l3 breaks up any tendency of the powderymaterial to arch in the region of the frame thus permitting an evendistribution of the aeriform fluid if used.

This system offers other advantages, particularly when the materialbeing handled comprises both a powdery material and large particles orsmall chunks or pellets.

When such a material is poured into a storage hopper it tends to pile upin a cone under the inlet spout. The fine material concentrates alongthe axis of the cone While the pellets roll down the sides of the coneand are then held against the edge by the pressure of the fineparticles. The combination of the vibration and a small air flowproduces a uniform flow of particles of all sizes whereas air alonerising through the bed of powdery material tends to fiuidize and liftthe powdery material while the heavier solid pellets readily dropthrough the fluidized bed so as to be the first material to be extractedwhen material is taken from the hopper. Conversely, when no fiuidizationis employed the large particles and pellets of material supplied throughthe chute 11 tend to roll to the side of the container as the cone ofmaterial forms in the hopper. The fine materials under this conditiontend to concentrate near the axis of the container directly under thespout ll and are the first to be withdrawn. With vibration of thecontainer walls the large particles of material tend to flow rapidlyalong the side of the wall thus holding the fine materials more or lesssuspended in the center of the hopper.

Vibratory agitators introduced into the container, as illustrated in thedrawings, allow control of these factors in that the vibration and smallamounts of air applied to the central portion of the hopper promote theflow of the finer materials as rapidly as the coarser materials therebymaintaining the proportions of such material relatively unchanged.

This improved vibratory structure also permits the use of a conditioninggas such as dry hot air for drying the powdery material as well as theuse of cold air in the event materials must be cooled or partiallyrefrigerated.

In ordinary operation in containers several feet in diameter and six toten feet high or more a vibration amplitude of 7a of an inch at 850 to900 cycles per minute in a vertical direction provides very satisfactoryagitation and also keeps the powdery material adjacent the agitatorsufiiciently free to provide uniform distribution of any air or othergas admitted through the arms.

Various modifications in the details of construction may readily be madewithout departing from the spirit and scope of the invention.

Having described the invention, I claim:

1. In an apparatus for handling a finely divided material confined in afled container, in combination, a skeleton frame positioned in thecontainer near the bottom thereof, the frame having an outline which isadapted to cover a substantial portion of a horizontal cross section ofthe fixed container, said frame including a plurality of perforatedtubular members, a tubular stem connected to said frame and extendingupwardly out of the container, a vibrator connected to the upper end ofthe stern and adapted to supply vibratory force to vibrate the frame,and means for forcing an aeriform fluid through said stem and perforatedtubular members for discharge through said finely divided material.

2. In an apparatus for handling a finely divided material confined in afixed container, in combination, a skeleton frame adapted to be immersedin the material in the container having an outline which covers asubstantial horizontal area of the container, said frame including aplurality of perforated tubular members, a stem connected to said frameand extending out of the material, a vibrator connected to the exposedend of the stem and adapted to produce vibration of the frame, and meansfor supplying an aeriform fluid to said tubular frame members fordischarge through said material.

3. In an apparatus for handling a finely divided material confined in afixed container, in combination, a skeleton frame adapted to be immersedin the material in the container and having an outline which covers asubstantial horizontal area of the container, said frame including aplurality of tubular members perforated along their upper surfaces,spaced'covers attached to said tubular members to shield theperforations from the material, a stem connected to said frame andextending out of the material, a vibrator connected to the end of thestem opposite the frame to produce vibration of the frame, and means forsupplying aeriform fiuid to said tubular members for discharge throughthe material in the container.

4. In an apparatus for handling a finely divided material confined in afixed container, in combination, a skeleton frame comprising a pluralityof radially extending perforated tubular members the outline of whichcovers a substantial area of the container adapted to be immersed in thematerial, a stem attached to the frame, a vibrator attached to the endof the stem opposite the frame adapted to produce vibration of saidframe, and means for supplying aeriform fluid to said perforated membersfor discharge through said material.

5. An apparatus according to claim 4 in which the aeriform fluid istransmitted through the stem connecting the vibrator to the frame.

6. In an apparatus according to claim 4 having covers spaced from andattached to the radially extending tubular members for dispersing theaeriform fluid and increasing the area of the vibrating frame.

7. In an apparatus for handling a finely divided ma terial in a fixedcontainer, in combination, a hollow perforated member having substantialhorizontal area adapted to be immersed in the material, a hollow sternconnected to the member, and a vibrator connected to the stern remotefrom the member and adapted to produce a vibration of said member alonga path having a substan tial component normal to said area, and meansfor supplying aeriform fluid to said member for discharge through theperforations and material thereabove.

8. In an apparatus according to claim 7, means connected to the hollowstem to force aeriform fluid into the stem for discharge through theperforations in the hollow member.

9. In an apparatus for handling a finely divided material in a fixedcontainer, in combination, a member adapted to be immersed in thematerial, said member being adapted to cover a substantial horizontalarea of the container, a stern connected to the member, a vibratorconnected to the stem remote from the member and adapted to producevibration of said member, and meansfor supplying aeriform fluid to thespace beneath the upper surface of the member for discharge through thematerial.

References Cited in the file of this patent UNITED STATES PATENTS1,586,374 Martin May 25, 1926 2,174,348 Damond Sept. 26, 1939 2,214,142Mall Sept. 10, 1940 2,347,267 lowers Apr. 25, 1944 2,353,346 Logan July11, 1944 2,569,085 Wood et a1 Sept. 25, 1951 2,652,175 Davis Sept. 15,1953 3,056,306 Muller Oct. 2, 1962.

FOREIGN PATENTS 828,091 Great Britain Feb. 17, 1960

9. IN AN APPARATUS FOR HANDLING A FINELY DIVIDED MATERIAL IN A FIXEDCONTAINER, IN COMBINATION, A MEMBER ADAPTED TO BE IMMERSED IN THEMATERIAL, SAID MEMBER BEING ADAPTED TO COVER A SUBSTANTIAL HORIZONTALAREA OF THE CONTAINER, A STEM CONNECTED TO THE MEMBER, A VIBRATORCONNECTED TO THE STEM REMOTE FROM THE MEMBER AND ADAPTED TO PRODUCEVIBRATION OF SAID MEMBER, AND MEANS FOR SUPPLYING AERIFORM FLUID TO THESPACE BENEATH THE UPPER SURFACE OF THE MEMBER FOR DISCHARGE THROUGH THEMATERIAL.